I. Field of the Invention
The present invention relates generally to double walled containment systems and the detection of leaks within double walled containment systems.
II. Description of the Related Art
The use of double walled containment systems has become an important part of industrial design in the modern world. For hundreds of years industrial processes have generated various unwanted and often dangerous byproducts. Modem industrial processes fall into many categories and produce byproducts in many different forms. A common technique for removing byproducts from the manufacturing process is by using fluids of various types to carry away those unwanted products. Typically, as the parts are made in the manufacturing process, a stream of fluid is directed to the area where the machine tool meets the part being manufactured. This fluid has numerous functions including lubrication, cooling and cleaning. Due to the numerous functions of the fluid, it typically contains many different types of chemical compounds which may be harmful to the environment. In order to remove the used fluids from the manufacturing process, the fluids are collected at the bottom of the machine producing the part and then directed into a flume system. A flume system usually consists of a series of troughs or gutters that direct fluids from various locations to a central location. By analogy, a flume system may resemble a system of tributaries, streams and rivers that flow into one another so as to direct a liquid from a variety of locations to one or more other locations. In an industrial setting, fluids are typically directed towards a reclamation or recycling process or to a disposal system.
Flume systems may be connected to machining systems, turning systems or even various electronics assembly systems. When designing a facility which utilizes machines which require connection to a flume system, the facility is preferably designed with the requirements of the flume system incorporated into the building design. Typically, the flume systems are designed into the floor and foundation of the facility. The floors should be constructed with specific types of concrete which meet the requirements of the machine tools to be installed on top of the foundation. Along with the various load requirements of the foundation, the foundation must also accommodate the flume system.
The current state of the art in design of flume systems requires that the flume be built into the foundation with a double walled containment system surrounding the flume system. This double walled system helps ensure that should the primary flume system fail, the dangerous products which may be running through the flume are not exposed to the concrete and underlying foundation of the facility. The current state of the art flume systems employ a J-shaped piece of extruded metal. The lower portion of the J-shaped piece forms a semi-circular bottom wall of the flume and the upwardly extending portion of the J-shaped piece defines one side wall. A flat piece of extruded metal is welded onto the end of the semi-circular bottom wall away from the first side wall and defines a second side wall. The completed flume has a U-shaped cross section with a weld at the base of one of the side walls. Following the welding of those two pieces, there is formed around the lower part of the flume another semi-circular piece of extruded metal which extends entirely around the semi-circular bottom wall and the area where the weld joins the bottom wall to the second side wall. The prior art systems were designed in this manner for a number of reasons. The primary reason was to move the weld from the bottom of the flume up to the side of the flume to reduce the impact of any leaks or breaks in the weld on the environment around the flume. By wrapping the double walled containment system entirely around the J portion of the flume, the designers could be fairly certain that any breaches in the welds would have minimal impact on the environment.
The prior art designs, however, have numerous problems. The initial problem with the prior art is the use of the two distinct pieces of extruded material which are non-interchangeable. The storage and handling of the J-shaped portion is difficult due to the overlap of the semi-circular portion, and forming a J-shaped portion is expensive.
The production of the double walled containment portion of the prior art flume systems is also problematic. A great deal of metal is required to produce the shape which will cover not only the weld section but also the entire lower portion of the flume system. Additional problems include the difficult placement of welds, precise shape of the double containment portion and difficult installation. Probably the most problematic area of the prior art systems is the detection of breaches in the welds to those flume systems. The prior art systems required complicated x-ray and inspection techniques in order to locate the breaches in the welds. Even systems which contained view ports into the lower portion of the double containment area do not facilitate the accurate location of breaches in the flume.
The present invention provides a double walled flume and leak detection system. The flume has a liquid containment wall with an outer surface and an inner surface. The flume is operable to contain a liquid therein. A secondary wall is joined to the liquid containment wall so as to define a secondary containment area. Specifically, the secondary wall has a first edge and second edge which are spaced apart and joined to the outer surface of the liquid containment wall. The secondary containment area is defined between the outer surface of the liquid containment wall and the secondary wall. A leak detection system communicates with the secondary containment area for detecting the presence of liquid in the secondary containment area.